Hi Allen,

Is it the oil service light or the oil pressure light? Either way you need to have it looked into immediately as, obviously, good oil is highly important to your engine's wellbeing. First thing to do is check the level manually using the dipstick. If it's perfect and the oil pressure light is on then it's probably just the oil light switch is faulty. This is inexpensive to replace so bring it back to the garage and ask them to do it. If that doesn't fix the issue then something else is amiss and it requires more investigation.

An oil service light should not come back on so soon, even if you are doing stop-start, low-speed driving all the time (which would degrade the oil quickly). I'd suggest bringing it back to the garage for analysis. Quickly plugging it into a diagnostic machine should reveal the reason.